Lowering device



March 1966 R. F. TREADWAY ETAL 3,238,577

LOWERING DEVICE Filed June 29. 1961 2 Sheets-Sheet l 7 v 34 so L it 38 2/ if 84 24 INVENTORS. 52 ROBERT F TREADWAY BILLY K. DAVIS March 1966 R. F. TREADWAY ETAL. 3,233,577

LOWERI NG DEVI CE 2 Sheets-Sheet 2 Filed June 29, 1961 INVENTORS. ROBERT E TREADWAY BILLY K. DAVIS 6 M Jazz FIG 4 OIL United States Patent 3,238,577 LOWERING DEVICE Robert F. Treadway and Billy K. Davis, Florence, Ala., assignors to Reynolds Metal Company, Richmond, Va., a corporation of Delaware Filed June 20, 1061, Ser. No. 120,540 6 Claims. (Cl. 22-57.2)

This invention relates generally to an object handling device and, more particularly, to a lowering device for a continuous rod or ingot.

In accordance with the present invention, there is provided a lowering device for continuously lowering an object such as an ingot at a substantially uniform rate. The lowering device comprises two sets of ingot-gripping means which alternately grip the ingot and lower it an incremental amount. The gripping and lowering means are operated by hydraulic devices automatically controlled by suitable valves.

Some of the principal advantages of this device are the following: it is fully automatic and the control system includes an interlock which provides an effective safety feature; it is capable of handling a rod or ingot of indefinite length; it is capable of use in any desired orientations, since operation is independent of gravity forces on the object being transported. In addition, the novel metering and back-pressure regllator arrangement employed provides positive control and operation at highly accurate withdrawal rates. Thus, the present device is particularly suitable for use in conjunction with the continuous casting system of copending application Serial No. 76,236 filed December 16, 1960 by John L. Dewey (now US. Patent 3,163,895).

For a better understanding of the invention and its various objects, advantages and details, reference is now made to the present preferred embodiment of the invention which is shown, for purposes of illustration only, in the accompanying drawings, wherein:

FIG. 1 is a front elevational view of an ingot-lowering device in accordance with the invention;

FIG. 2 is a cross sectional view taken along lines 22 of FIG. 1;

FIG. 3 is a cross sectional view taken along lines 33 of FIG. 1; and

FIG. 4 is a schematic diagram of a preferred hydraulic system for operating the apparatus shown in the previous figures.

In FIG. 1, there is shown a base above which is rnonuted a casting apparatus (not shown). An ingot 12 is formed by the casting apparatus and is extracted downwardly therefrom. The ingot extends through apertures 14 and 16 in vertically aligned upper and lower platens 18 and 20. Rigidly affixed to base 10 are a pair of actuators 22 and 24 for raising and lowering upper platen 18. Actuator 22 has a cylindrical bore within which is disposed piston 26 having a piston rod 28 fixed to one side of upper platen 18. Another actuator 24 similarly contains a piston 30 having a piston rod 32 connected to the opposite side of platen 18. Conduits 34 and 36 are connected to the upper and lower ends, respectively, of actuator 22 for selectively operating piston 26 from a source of hydraulic pressure, as described below in connection with FIG. 4. In addition, conduits 38 and 40 are connected to the upper and lower ends, respectively, of actuator 24 and are adapted for selectively applying hydraulic pressure to piston 30. Platen 18 is raised or lowered, depending upon which end of the actuators 22 and 24 have pressure applied thereto.

In like manner, a second pair of actuators 42 and 44 are provided for raising and lowering lower platen 20. The operation of actuators 42 and 44 (relative to lower 3,238,577 Patented Mar. 8, 1966 ICC platen 20) is the same as the operation of actuators 22 and 24 on upper platen 18. Thus, actuator 42 contains a piston 46 including a piston rod 48 fixed to one side of platen 20, as seen in FIG. 1, and actuator 44 has a piston 45 and piston rod 47. Furthermore, cylinder 42 is provided with an upper conduit 50 and a lower conduit 5-2 for selectively operating piston 46. An upper conduit 53 and a lower conduit 51 are similarly connected to cylinder 44. Therefore, it can be seen that cylinders 42 and 44 may be hydraulically energized to raise and lower platen 20.

Mounted on upper platen 18 by means of a bracket 54 is a locking cylinder 56 containing a piston 58 including a piston rod 60. A lever 62 is pivotally mounted at one end thereof to rod 60 and is attached at the other end thereof to an annular locking plate 64. Locking plate 64 is rotatably mounted on a base plate 66 which in turn is fixed to upper platen 18. Three notches, 68a, [2, c are formed in the inner periphery of locking plate 64. Three corresponding locking cams 70a, b, c are pivotally mounted on base plate 66. Formed on each cam 70 is an upstanding projection 72 which is disposed within a corresponding notch 68.

Conduits 74 and 76 are connected to opposite ends of locking cylinder 56 for selectively applying thereto a source of hydraulic pressure. It can be seen that when pressure is applied to conduit 76, piston rod 60 will be actuated to turn locking plate 64 in a counterclockwise direction as shown in FIG. 2, thereby pivoting the locking cams 70 out of engagement with ingot 12. How ever, when pressure is applied to conduit 74, locking plate 64 is turned in a clockwise direction and thereby pivots locking cams 70 into gripping engagement with ingot 12.

Mounted on upper platen 18 is a three-port spring return pilot valve V having an upstanding operator 80. Directly above operator 80 is a stop 82 adjustably mounted on a rod 84 fixed to base 10. When actuators 22 and 24 carry platen 18 to its upwardmost position, operator 80 engages stop 82 to actuate valve V for purposes described below. Also mounted on platen 18 is a spring return valve V having a horizontally extending operator 88. Attached to locking plate 64 is a tab which is adapted to engage operator 88 when looking plate 64 is rotated in a clockwise direction sufliciently for the locking cams to firmly grip the ingot. Such engagement of tab 90 opens valve V in a manner and for a purpose described below.

Fixed to the underside of platen 18 is a rod 92 on which is adjustably mounted another stop 94. Mounted on platen 20 immediately below stop 94 is a pilot valve V similar to valve V When upper platen 18 is in its lowermost position and platen 20 is in its uppermost position, an operator 98 projecting upwardly from valve V engages stop 94 to operate valve V in a manner described below.

The lower platen 20, shown in FIG. 3, has associated therewith components which correspond to those described for upper platen 18. For example, a locking cylinder 100 is mounted by bracket 102 to platen 20. Piston rod 104 drives circular locking plate 106 in a rotary direction which is determined by which one of the conduits 108 and 110 is connected to a supply of hydraulic pressure. Locking cams 112 are shown in engagement with ingot 12 indicating that conduit 110 is connected to a pressure source to rotate locking plate 106 in a clockwise direction. Also mounted on platen 20 is a limit valve V (similar to valve V having a spring biased operator 114 adapted to cooperate with the tab 116 mounted on locking plate 106.

The operation of the apparatus shown in FIGS. 1, 2

and 3 will now be discussed in conjunction with the hydraulic schematic diagram shown in FIG. 4. Where appropriate, corresponding items in FIGS. 1-4 bear the same reference numerals.

A pump 120 of adequate capacity to operate the lowering device shown in FIG. 1 furnishes fluid under pressure from a sump 122. The fluid is pumped along a pressure line 124 and is returned to sump 122 via return line 126. A pressure relief valve 128 is connected across lines 124 and 126 at the outlet of pump 120, and a check valve 127 is in line 124 at the outlet of pump 120. A conventional accumulator 129 may be provided at the end of line 124 in a manner well known in hydraulic servomotor systems. However, the use of an accumulator is a matter of choice and depends upon the operating characteristics of the pump.

Parallel feed lines 130 and 132 are tapped oil the main pressure line 124 and are connected to pressure inlet ports P and P of control valves V and V Valves V and V are four-way reversing valves which respectively control the hydraulic operation of platens 18 and 20. Since the operation of valves V and V is identical, only the operation of valve V will be described in detail. In addition to the pressure inlet port P valve V also has two control ports A and B and an exhaust port E Valve V may be controlled in a manner as described below so that it has a first condition where pressure from line 130 is applied to port P and transmitted to control port A while control port B communicates with exhaust port E In its second condition, port P communicates with port B and port E communicates with port A In FIG. 4, control valve V is shown in its second condition whereas control valve V is shown in its first condition.

Let us now assume that platen 18 has just reached its uppermost position and platen 20 is in its lowermost position. The three-way spool valve V acts as an external pilot for the four-way control valve V Under the conditions just assumed, operator 80 of pilot valve V has just engaged stop 82. Depression of operator 80 forms a flow path through valve V between a pilot line 134 and pressure return line 126, thereby exhausting the pressure from pilot line 134. Thus, valve V is actuated to its second condition where pressure port P communicates with control port B and hydraulic pressure from line 130 is applied to control port B Consequently, hydraulic pressure is applied from line 130 through control port B via lines 136 and 138 to conduits 34 and 38 which communicate respectively with the upper ends of actuator 22 and 24. Pressure is also applied via line 136 to line 140 which communicates with conduit 74 to apply pressure to cylinder 56, thereby actuating piston 58 and piston rod 60. Pressure is exhausted from the opposite end of cylinder 56 through lines 76 and 166 and ports A and E of valve V to the system return line 126.

The movement of piston rod 60 is transmitted through lever 62 to turn locking plate 64 in a clockwise direction, thereby pivoting locking cams 70 into gripping engagement wtih ingot 12. FIG. 2 shows the position of the locking plate and cams prior to the application of pressure to conduit 74 of cylinder 56. As locking plate 64 turns, tab 90 engages the operator 88 on the two-port valve V which pressurizes control valve V through its associated external pilot valve V Tab 90 depresses operator 88 to open normally closed valve V so that line pressure is applied via line 142 through valve V to conduit 144. Fluid pressure is transmitted through valve V and conduit 144 to one port of the three-way spring return spool valve V which acts as the external pilot for the control valve V Actuator 98 of pilot valve V is initially biased in its normal upward position so that line 144 applies pressure through the valve to the pilot line 146 of control valve V The pressure applied along line 146 causes valve V to be placed in its first condition (as shown in FIG. 4), which is the reverse of that just described for the exhausted control valve V which is in its second condition.

With valve V in its first condition, fluid pressure is applied along line 132 to the pressure inlet port P of valve V which is in communication with the control port A Pressure is then applied through line 148 to conduit 108 to apply pressure to the top of piston 103 carried within lock cylinder 100. FIG. 3 shows locking plate 106 and locking cams 112 in gripping engagement with ingot 12 before pressure is applied to cylinder 100. As pressure is applied through conduit 108, piston rod 104 and lever 105 move locking plate 106 in a counterclockwise direction to pivot locking cams 112 out of engagement with ingot 12. Pressure is exhausted from cylinder 100 through conduit 110, line 160 and ports B and E of valve V to line 126. Tab 116 is rotated out of engagement with the spring biased actuator 114 to close limit valve V Pressure is also applied from port A and line 148 through a check valve 150, by-passing the metering device 174 (hereinafter discussed), to line 152 which communicates with the lower conduits 52 and 51 connected re spectively to the lower end of lowering cylinders 42 and 44. The oil pressure applied to cylinders 42 and 44 causes their corresponding pistons to move upwardly carrying with them their associated piston rods 48 and 47 and platen 20 to which the piston rods are secured. Platen 20 continues upwardly until the piston in cylinders 42 and 44 reach the ends of their strokes, whereupon platen 20 stops and waits until platen 18 reaches its lowermost position. Pressure in the upper ends of cylinders 42 and 44 is exhausted through conduits 50 and 53, lines 164, 162

and through the ports B and E of control valve V to the system return line 126.

Due to the pressure in the uper ends of lowering cylinders 22 and 24, pistons 26 and 30 move platen 18 downwardly until stop 94 engages valve actuator 98 of limit valve V mounted on lower platen 20. Depression of actuator 98 reverses valve V so that pilot line 146 is communicated to line 158 and to the system return line 126, thereby exhausting the actuating pressure from control valve V Valve V is thereby reversed from the first condition shown in FIG. 4 and is placed in its second condition where inlet pressure port P communicates with the control port B and exhaust. port E communicates with control port A Line pressure is thereby applied via line 132, valve V lines 160, 162 and 164, and conduits 50 and 53 to the tops of cylinders 42 and 44, respectively.

Pressure is also applied via line ,160 to conduit communicating with the lower end of locking cylinder 100 mounted on platen 20, thereby causing piston rod 104 to turn locking plate 106 in a clockwise direction so that locking cams 112 are pivoted into gripping engagement with ingot 12 as shown in FIG. 3. Movement of locking plate 106 causes tab 116 to depress actuator 114 thereby opening valve V Pressure is then applied from line 162 through valve V to the pilot valve V Valve operator 80 is initially in its normally biased upwardly position since it is out of engagement with stop 82. Therefore, valve V is pressurized through pilot valve V and pilot line 134 so that inlet pressure port P communicates with control port A and exhaust port E communicates with control port B i.e., valve V is placed in its first condition.

Fluid pressure is thereby applied through valve V from line to line 166, via check valve 168 to line 170 and the conduits 36 and 40 connected respectively to the lower ends of actuators 22 and 24. Pressure is also applied via line 166 to the conduit 76 connected to the upper end of lock cylinder 56. As shown in FIG. 2, this causes piston rod 60 to turn locking plate 64 in a counterclockwise direction thereby disengaging locking cams 70 from ingot 12 and releasing operator 88 so that limit valve V is closed. Cylinder 56 exhausts through conduit 74 lines 140 and 136 and through ports B and E of valve V to line 126. The pressure applied to actuators 22 and 24- via conduits 36 and 40 causes piston rods 28 and 32 to raise platen 18 until it reaches its maximum upward position where stop 82 engages valve operator 80 on pilot valve V Vpl is thereby actuated to exhaust the pressure from pilot line 134 to system return line 126 and the cycle is repeated.

When actuators 22 and 24 are lowering platen 18, oil pressure is exhausted through the bottom of the cylinders via conduits 36 and 40, line 170 and then through a metering device 172 and ports A and E of valve V to system return line 126. Check valve 168 blocks oil flow in this direction so that the oil flows completely through metering device 172 during this part of the cycle. Metering device 172 is an adjustable volume pump which supplies fluid at a substantially constant rate, for a given setting of the control. The back-pressure valve 200 is set higher than the maximum pressure expected in line 170. Thus, the lowering rate is controlled by metering the flow from the actuators 22, 24 during lowering of the ingot. Metering device 174, check valve 150 and back-pressure regulator valve 201 serve similar functions in respect to lowering cylinders 42 and 44. The adjusting controls 176 and 178 on metering devices 172 and 174, respectively, are mechanically interconnected so that their settings are identical to assure that platens 18 and 20 have the same rate of descent.

From the foregoing description and accompanying drawings, it can be seen that there has been provided a fully automatic lowering apparatus suitable for lowering a rod or ingot from a continuous casting apparatus. While the preferred embodiment described above shows the lowering cylinders 22, 24, 42, and 44 to be fixed and their associated internal pistons as movable, it is to be understood to be within the scope of this invention alternatively to fix the pistons to floor and the cylinders to platens 1S and 21 so that the cylinders, rather than the pistons, are moved to raise and lower the platens. Also, while the invention has been illustrated in a vertical orientation, it is likewise adapted for operation in other inclinations as, for example, in a horizontal casting unit.

Furthermore, while the hydraulic motive system disclosed is particularly preferred, it will be apparent that the control system therefor (and especially the sensing devices) may constitute pneumatic or electrical limit switches.

While a present preferred embodiment of the invention has been illustrated and described, it will be recognized that the inventiOn may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. In combination with an ingot casting unit, apparatus for lowering the ingot from a continuous casting unit, comprising first and second platens having vertically aligned apertures to receive the ingot for passage therethrough; at least one of said platens being adapted for substantially continuous reciprocating movement in the ingot-lowering direction, and the other of said platens being adapted for intermittent reciprocating movement, first and second ingot-gripping means carried respectively by said platens for gripping the ingot adjacent said apertures, first hydraulic means for operating said first gripping means to grip the ingot, second hydraulic means for operating said second gripping means to grip the ingot, a base, third hydraulic means including a piston-cylinder mechanism connected between said first platen and the base for reciprocating said first platen vertically relative to said base, fourth hydraulic means including a piston-cylinder mechanism connected between said second platen and the base for reciprocating said second platen vertically relative to said base, first valve means tor connecting said first and third hydraulic means to a source of hydraulic pressure, second valve means for connecting said second and fourth hydraulic means to a source of hydraulic pressure, first control means responsive to an upper vertical position of said first platen to actuate said first valve means to a first condition to connect said first and third hydraulic means to the pressure source, there-by operating said first gripping means to an ingot-gripping condition, moving said first platen downwardly to a second vertical position and lowering the ingot therewith, second control means responsive to the second position of said first platen to actuate said second valve means to a first condition to connect said second and fourth hydraulic means to the pressure source, thereby operating said second gripping means to an ingotgripping condition, moving said second platen downwardly and continuing to lower the ingot without interruption, third control means responsive to the actuation of said second gripping means to actuate said first valve means to a second condition whereby said first gripping means is released from the ingot and said first platen is returned to its said upper vertical posit-ion, and fourth control means responsive to the operation of said first gripping means to actuate said second valve means to a second condition whereby said second gripping means is released trom the ingot and said second platen is returned to its uppermost position.

2. In combination with an ingot casting unit, apparatus for continuously withdrawing the ingot at a substantially'uniform rate, comprising first and second ingotgripping means for transporting the ingot outwardly from said casting unit at a substantially uniform rate of motion in a forward direction, first and second movable platens respectively carrying said gripping means and mounted for movement along adjacent paths spaced lengthwise of the ingot, said first platen being adapted for substantially continuous reciprocating movement away from and back to an initial position, means responsive to said initial position of the first platen to cause said first gripping means to grip the ingot and carry it forward at the desired substantially uniform rate, means responsive to a subsequent position of said first platen to cause the second gripping means to grip the ingot together with said first gripping means and to move the second platen forwardly, thereby continuing said forward motion of the ingot without interruption; said second platen and gripping means being adapted to transport the ingot while the first gripping means is disengaged from the ingot and said first platen is returning to said initial position, means synchronizing the rates of motion of said first and second platens while both are moving in said forward direction, means for automatically releasing said first gripping means npon the gripping of the ingot by said second gripping means, and means for returning the first platen to its initial position.

3. In combination with an ingot casting unit, apparatus for continuously withdrawing the ingot at a substantially uniform rate, comprising a base; first and second movable platens mounted for reciprocating movement relative to said base in the ingot-withdrawal direction, said platens respectively carrying ingot-gripping means adapted to grip the ingot alternately as it emerges from the casting unit; the gripping means of each platen being arranged to grip the ingot before the release thereof by the gripping means of the other platen; and an actuator system for each of said platens, including a plurality of pistoncylinder mechanisms connected between the platen and said base for simultaneous operation to translate said platen and its gripping means outwardly from said casting unit at a substantially uniform rate, means for applying pressure to one side of the piston in each cylinder to move said platen and gripping means in the ingot withdrawal direction, the movement of each piston in response to said pressure being resisted by hydraulic fluid filling the cylinder on the opposite side of the piston, and a metering device for controlling the rate at which said fluid is evacuated as the pistons move in response-to said pressure; and means coordinating said metering devices to achieve the same rates of movement of said platens in the ingot-withdrawal direction.

4. Apparatus according to claim 3, wherein said interlock is initiated by a sensing device associated with one of said gripping means and adapted to detect a relative position of the other gripping means.

5. In combination with an ingot casting unit, apparatus for continuously withdrawing the ingot at a substantially uniform rate, comprising a base; first and second movable platens mounted for reciprocating movement relative to said base in the ingot-withdrawal direction, said platens respectively carrying first and second ingot-gripping means adapted to grip the ingot alternately at spaced intervals longitudinally thereof; an actuator system for said first platen, including a plurality of piston-cylinder mechanisms connected between the platen and said base for simultaneous operation to translate said first platen and gripping means relative to the base, means responsive to an initial position of said first platen for applying pressure to one side of the piston in each cylinder to move said first platen to a subsequent position in the ingot withdrawal direction, the movement of each piston in vresponse to said pressure being resisted by substantiallyincompressible fluid filling the cylinder on the opposite side of the piston, means for actuating said mechanisms -by evacuating the fluid from said cylinders at a controlled rate, thereby coordinating the displacements of said pistons and translating said first platen and ingot-gripping means in the ingot withdrawal direction at a substantially uniform rate, and means operative upon the actuation of said piston-cylinder mechanisms to cause said first gripping means to grip the ingot; a corresponding actuator system for said second platen; means responsive to the aforesaid subsequent position of said first platen for causing the second gripping means also to grip the ingot and for operating the latter actuator in synchronization with the actuator for said first platen, thereby continuing the translation of said ingotin the'withdrawal direction .at the aforesaid rate without interruption; and means responsive to gripping of the ingot by said second gripping means to release said first gripping means and return it to the initial position.

6. In combination with an ingot casting unit, apparatus for continuously lowering the ingot at a substantially uniform rate, comprising first and second ingot-gripping means adapted respectively to move outwardly from said casting unit in gripping engagement with the ingot, said first gripping means being mounted for substantially continuous reciprocating movement back and forth between upper and lower positions along a path of travel in the ingot-lowering direction, and said second gripping means being mounted for reciprocating movement away from and back to a dwell position along a path of travel spaced lengthwise of the ingot from that of said first gripping means; means, other than the ingot, synchronizing the rates of motion of said first and second ingot-gripping means while both are moving outwardly from the casting unit; first and second power means for respectively actuating said first and second gripping means to grip the ingot; first control means responsive to said upper position of the first gripping means to operate said first power means and thereby cause said first gripping means to grip the ingot; means coordinated with the gripping of the ingot by the first gripping means to lower said first gripping means at a substantially uniform rate toward its lower position; second control means responsive to said lower position of the first gripping means to operate said second power means and thereby cause said second gripping means also to grip the ingot; means coordinated with the gripping of the ingot by the second gripping means to lower said sec ond gripping means and thereby continue lowering the ingot' at the aforesaid rate without interruption; means to release said first gripping means upon the gripping of the ingot by said second gripping means and for returning the first gripping means to its upper position; and means to release said second gripping means upon the gripping of the ingot by said first gripping means at said upper position and for returning the second gripping means to its dwell position in preparation for another similar cycle of operation.

References Cited by the Examiner UNITED STATES PATENTS 2,206,459 7/1940 Hagemeyer 22-47 2,215,169 9/1940 Beeston 97 2,374,630 4/1945 Tucker 60-97 2,555,476 6/1951 Du Bois et al 1 22-92 2,808,627 10/1957 Venus 2292 2,858,105 10/1958 Lucas 254-107 2,895,190 7/ 1959 Bungeroth et a1 Q2/57.'2 2,920,870 1/1 960 Suderow 254* XR 2,992,812 7/196 1 Rasmussen et al 254-107 FOREIGN PATENTS 725,429 3/ 1955 Great Britain.

J. SPENCER OVERHOLSER, Primary Examiner.

MARCUS U. LYONS, MICHAEL V. BRINDI-SI, ROB- ERT F. WHITE, Examiners. 

6. IN COMBINATION WITH AN INGOT CASTING UNIT, APPARATUS FOR CONTINUOUSLY LOWERING THE INGOT AT A SUBSTANTIALLY UNIFORM RATE, COMPRISING FIRST AND SECOND INGOT-GRIPPING MEANS ADAPTED RESPECTIVELY TO MOVE OUTWARDLY FROM SAID CASTING UNIT IN GRIPPING ENGAGEMENT WITH THE INGOT, SAID FIRST GRIPPING MEANS BEING MOUNTED FOR SUBSTANTIALLY CONTINUOUS RECIPROCATING MOVEMENT BACK AND FORTH BETWEEN UPPER AND LOWER POSITIONS ALONG A PATH OF TRAVEL IN THE INGOT-LOWERING DIRECTION, AND SAID SECOND GRIPPING MEANS BEING MOUNTED FOR RECIPROCATING MOVEMENT AWAY FROM AND BACK TO A DWELL POSITION BEING A PAHT OF A TRAVEL SPACED LENGTHWISE OF THE INGOT FROM THAT OF SAID FIRST GRIPPING MEANS; MEANS, OTHER THAN THE INGOT, SYNCHRONIZING THE RATES OF MOTION OF SAID FIRST AND SECOND INGOT-GRIPPING MEANS WHILE BOTH ARE MOVING OUTWARDLY FROM THE CASTING UNIT; FIRST AND SECOND GRIPPING MEANS FOR RESPECTIVELY ACTUATING SAID FIRST AND SECOND GRIPPING MEANS TO GRIP THE INGOTFIRST CONTROL MEANS RESPONSIVE TO SAID UPPER POSITION OF THE FIRST GRIPPING MEANS TO OPERATE SAID FIRST POWER MEANS AND THEREBY CAUSE SAID FIRST GRIPPING MEANS TO GRIP THE INGOT; MEANS COORDINATED WITH THE GRIPPING OF THE INGOT BY THE FIRST GRIPPING MEANS TO LOWER SAID FIRST GRIPPING MEANS AT A SUBSTANTIALLY UNIFORM RATE TOWARD IS LOWER POSITION; SECOND CONTROL MEANS RESPONSIVE TO SAID LOWER POSITION; THE FIRST GRIPPING MEANS TO OPERATE SAID SECOND POWER MEANS AND THEREBY CAUSE SAID SECOND GRIPPING MEANS ALSO TO GRIP THE INGOT; MEANS COORDINATED WITH THE GRIPPING OF THE INGOT BY THE SECOND GRIPPING MEANS TO LOWER SAID SECOND GRIPPING MEANS AND THEREBY CONTINUE LOWERING THE INGOT AT THE AFORESAID RATE WITHOIUT INTERRUPTION; MEANS TO RELEASE SAID FIRST GRIPPING MEANS UPON THE GRIPPING OF THE INGOT BY SAID SECOND GRIPPING MEANS AND FOR RETURNING THE FIRST GRIPPING MEANS TO ITS UPPER POSITION; AND MEANS TO RELEASE SAID SECOND GRIPPING MEANS UPON THE GRIPPING OF THE INGOT BY SAID FIRST GRIPPING MEANS AT SAID UPPER POSITION AND FOR RETURNING THE SECOND GRIPPING MEANS TO ITS DWELL POSITION IN PREPARATION FOR ANOTHER SIMILAR CYCLE OF OPERATION. 